Liquid stabilizer system for polyvinyl chloride

ABSTRACT

Homogeneous liquid stabilizer compositions are provided which are useful with polyvinyl chloride resins to impart improved antistatic and antifogging properties in addition to stabilizing the resins. The stabilizer solutions are obtained using a specific procedure for blending the individual stabilizer components.

United States Patent Rhodes et al. 5] Dec. 23, 1975 [5 LIQUID STABILIZERSYSTEM FOR 2.997.454 8/196! 1.61m"......................... 260/45.8 RPQLYVINYL CHLORIDE 3,202,622 8/1965 Scullin 260/23 XA 3,255,l36 6/l966Becker et al. 260/4595 lnvenwrsr Phlllll W Robert L. 3.558.537 1/1971Hecker et al. 260/23 XA both of Cincinnati. Ohio 3.575.905 4/1971 Rhodes260/23 XA 3,640,953 2/1972 Brecker et al. 260/23 XA [73] Assgnee' g gcmcmnat" 3.682,853 8/1972 Barie Ct 260/23 XA [22] Filed: 1973 PrimaryExaminer-Dor1ald E. Czaja [2|] App]. No 338,163 AssistantExaminer-William E. Parker Related Us. Application Data gioemey, Agent,or Firm-Gerald A. Baracka; John D. [62] Division of Ser. No. 226,273.Feb. I4, 1972, Pat. No.

[57] ABSTRACT [52] US. Cl. 260/23 XA; 252/406; 260/217 H;

260/457 P; 260/4575 R Homogeneous liquid stabilizer compositions arepro- [51] Int. Cl. C08L 91/00 vided which are useful with polyvinylchloride resins [58] Field of Search 260/23 XA, 23.7 H, 45.7 P, toimpart improvedantistatic and antifogging proper- 260/4575 R, 45.85 R,45.95; 252/400 ties in addition to stabilizing the resins. Thestabilizer solutions are obtained using a specific procedure for [56]References Cited blending the individual stabilizer component's. UNHEDSTATES PATENTS 5 Claim N D" 2.711.401 6/1955 Lally r. 260/23 XA 0 LIQUIDSTABILIZER SYSTEM FOR POLYVINYL CHLORIDE This is a division ofapplication Ser. No. 226,273 filed Feb. 14, 1972, now issued as US. Pat.No. 3,756,200.

BACKGROUND OF THE INVENTION Multi-component stabilizers are extensivelyutilized for the stabilization of polyvinyl chloride resins. Suchstabilizer systems, sometimes referred to as stabilizer packages, arecommonly employed due to the inability of any one material tosufficiently protect the resins against oxidative, thermal andphotochemical degradation and to impart other desirable properties tothe end products. In order for a stabilizer package to be effective, itmust not only be capable of protecting the polyvinyl chloride resinagainst loss of physical properties, discoloration or loss of opticalclarity, embrittlement, etc., by preventing polymer degradation, but itshould also be capable of being readily and uniformly dispersed in theresin. Additionally, the stabilizer system must be compatible with andcomplement other additives employed for specific end-use applicationssuch as, for example, in food packaging, where antifogging andantistatic properties of the plastic compositions are essential.

One such useful multi-component additive system has recently beendescribed in US. Pat. No. 3,558,537. This patent provides polyvinylchloride resin compositions characterized by having good stability andimproved resistance to fogging. The resins stabilized in accordance withthis invention are useful for transparent plastic wraps, especially foruse with high moisture content items such as food products. Thestabilizer/antifogging system of the U.S. Pat. No. 3,558,537 iscomprised of partial esters derived from polyglycerol and unsaturatedfatty acids, a zinc salt of a monocarboxylic fatty acid and may alsocontain one or more other additives or modifiers. A particularly usefulembodiment of the invention employs the partial ester and zinc salt incombination with an epoxy plasticizer and phosphite stabilizer.

While the stabilizer package described in the US. Pat. No. 3,558,537imparts extremely useful properties to the resin, it is not withoutcertain disadvantages. The four-compartment stabilizer compositionsobtained in accordance with the invention are pastes. The compositionsdo not flow readily at ambient conditions and are often lumpy,heterogeneous masses. These features present processing problems such asinability or difficulty of pumping with conventional process equipment.Another problem associated with the use of the pasty stabilizers of theUS. Pat. No. 3,558,537 is the difficulty in obtaining uniform dispersionof the mass in the polyvinyl chloride resin. The greatest drawback,however, is the tendency for phase separation (oil settles to thebottom) after preparation and upon standing. While not insurmountable,these problems do complicate the processing and equipment required ifsuch a stabilizer system is to be employed.

It would be extremely useful and advantageous if a homogeneous liquidstabilizer package capable of imparting improved stabilization andantilogging and antistatic properties to polyvinyl chloride resin wereavailable. It would be especially useful if such a stabilizer packagewas not susceptible to phase separation upon standing. Such a stabilizercomposition could be easily handled and incorporated into polyvinylchloride com- 2 positions and homogeneous blends, uniform from batch tobatch, obtained therewith. An additional economic advantage would resultdue to the ability to employ simplified process equipment with such aliquid stabilizer package.

SUMMARY OF THE INVENTION In accordance with the present invention it ispossible to prepare homogeneous liquid stabilizer systems capable ofimparting improved antifogging and antistatic properties to polyvinylchloride resins in addition to stabilizing said resin compositions. Thestabilizer solutions are comprised of a partial ester of a polyglycerol,a metal salt of a monocarboxylic fatty acid, an epoxy plasticizer and anorganic phosphorous compound. They are homogeneous solutions which donot undergo phase separation when allowed to stand at ambient conditionsfor prolonged periods. The instant stabilizer compositions are obtainedthrough the utilization of a specific blending technique which consistsof first forming a solution of the metal salt, the epoxy compound andthe organo-phosphorous compound by heating at a temperature from aboutl25C up to about 200C to effect solution. The polyglycerol partial esteris then added to the resulting clear uniform solution and blendedtherewith. Stabilizer systems prepared following this procedure areliquids which do not separate upon standing and which can be readilyblended with polyvinyl chloride employing conventional processequipment. The so-prepared liquid stabilizer may also be blended withplasticizers and employed as a masterbatch. Polyvinyl chloride resinscompounded with the present liquid stabilizers exhibit a high degree ofresistivity to oxidative, thermal and photochemical degradation as wellas having improved antistatic and antifogging properties.

DETAILED DESCRIPTION In accordance with the present inventionhomogeneous liquid stabilizer systems are obtained by the addition ofpartial esters of polyglycerols to a solution comprised of metal saltsof carboxylic acids, organo-phosphorous compounds and epoxy compounds.

Any epoxy compound capable of functioning as a plasticizer may beemployed to dissolve the metal carboxylate and organophosphorouscompound but epoxidized oils are especially preferred. The epoxycompound will contain one or more epoxy groups per molecule and may beeither aliphatic, cycloaliphatic, aromatic or heterocyclic in nature.Preferably, aliphatic or cycloaliphatic epoxy compounds containing fromabout l() to I carbon atoms, and more preferably from about 20 to carbonatoms, will be employed. Epoxy higher ester compounds known to beeffective plasticizing agents are useful for this invention. Such estersmay be derived from unsaturated alcohols and/or unsaturated acidswherein the ester is subsequently epoxidized at the site of theunsaturation. Alternatively, the unsaturated acid or alcohol may beepoxidized prior to the esterfication reaction. Typical unsaturatedacids for this purpose are oleic, linoleic, linolenic, erucic andricinoleic acids. These may be esterified with monohydric or polyhydricalcohols or mixtures thereof. Useful monohydric alcohols includebutanol, Z-ethylhexanol, octanol, isooctanol, lauryl alcohol, stearylalcohol, oleyl alcohol and the like. Polyhydric alcohols may includepentaerythritol, ethylene glycol, l,2-propylene glycol, l,4-butyleneglycol, neopentyl glycol, glycerol, mannitol, sorbitol, ricinoleylalcohol, and the like. The polyhydric alcohols may be fully or partiallyesterified.

Especially useful epoxy compounds for the instant invention are theepoxidized naturally occurring oils which consist of mixtures of higherfatty acid esters. Suitable oils include epoxidized soybean oil,epoxidized olive oil, epoxidized cottonseed oil, epoxidized coconut oil,epoxidized tall oil fatty acid esters, epoxidized tallow and the like.As an especially preferred embodiment of the present inventionepoxidized soybean oil is employed. The useful epoxidized oils may beobtained by any known epoxidation method, such as the formic acid andsulfuric acid processes, employing any of the known epoxidizing agents.

Still other epoxy compounds may be present in combination with theaforementioned epoxy plasticizers. These epoxy compounds are usually noteffective plasticizers but may be desirable in small amounts for thestabilizing properties which they impart. Typical epoxy compounds ofthis latter type are the epoxidized monocarboxylic acids, glycidylethers of polyhydric alcohols and phenols, epoxy polyethers ofpolyhydric phenols and the like. These epoxy stabilizers will generallynot exceed about weight percent of the total epoxy compound.

The metal carboxylate dissolved in the epoxy plasticizer is a'polyvalentmetal salt of a monocarboxylic organic acid containing from 6 to 36carbon atoms. Preferably the acid will be an aliphatic monocarboxylicacid containing from about l2 to carbon atoms. Mixed acids and mixedpolyvalent metals may be employed to yield useful salts for thisinvention. The mixed fatty acids are derived from fats and oils such astallow, coconut oil, cottonseed oil, soybean oil, corn oil, peanut oilor the like. Typical acids which can be employed are the following:caproic acid, capric acid, 2-ethylhexanoic acid, caprylic acid,pelargonic acid, hendecanoic acid, lauric acid, palmitic acid, stearicacid and the like. The polyvalent metals are preferably divalent metalssuch as barium, calcium, magnesium, zinc, cadmium, tin, copper, iron,cobalt and nickel. Especially useful divalent metals are calcium andzinc or mixtures thereof since these are suitable for use in nontoxicapplications such as when the polyvinyl chloride resin is to be used forfood-packaging film. Excellent results are obtained when zinc stearateis the metal carboxylate employed with the epoxy compound andorganophosphorous compound.

Also dissolved in the epoxy plasticizer with the metal carboxylatecompound is an organophosphorous compound. The organophosphorousstabilizer compounds useful for this invention are phosphites containingat least one -O-R group bonded to the phosphorous atom wherein R is ahydrocarbon radical such as aryl, alkyl, alkaryl, aralkyl andcycloaliphatic or a heterocyclic group. In general, the aforementioned Rgroups will contain from about 1 to about carbon atoms and morepreferably contain from about 6 to 20 carbon atoms. The phosphites ofthis invention are represented by the general formula wherein R is oneof the above-defined groups and R' and R" are hydrogen or a radical asdefined above for R. The R groups may be the same or they may differ.Phosphite stabilizer compounds of the above type include monophenylphosphite, diphenyl phosphite, triphenyl phosphite, tricresyl phosphite,tri(octylphenyl) phosphite, tri(p-tert-nonylphenyl) phosphite, tri(-nonylphenyl) phosphite, tribenzyl phosphite, tri(2- cyclohexyl)phosphite, tricyclohexyl phosphite, tricyclopentyl phosphite.tri(tetrahydrofurfuryl) phosphite, monoisooctyl phosphite, diisooctylphosphite, triisooctyl phosphite, tridodecyl phosphite, diisooctylphenyl phosphite, diphenyl decyl phosphite, issoctyl diphenyl phosphite,tri(2-ethylhexy1) phosphite and the like. Also useful are phosphitecompounds wherein R and R" join to form ring systems illustrated in theformulae wherein R' is a bivalent hydrocarbon radical and R is amonovalent radical, as previously defined, or a divalent radical derivedtherefrom. Triphosphites, that is, where R, R and R" are all hydrocarbonradicals, either the same or different, are a preferred embodiment ofthe instant invention. Tri(alkaryl) phosphites are especially preferredwith tri(nonylphenyl) phosphite being especially useful since thisphosphite has been approved by the Food and Drug Administration for usein polyvinyl chloride resin films for food packaging applications.

To achieve the desirable stabilizer compositions of the presentinvention, that is, highly effective liquid stabilizers, it is necessarythat the metal carboxylate and phosphite compound, with any additionalstabilizer components if such are to be employed, be dissolved in theepoxy compound prior to the addition of the polyglycerol partial ester.This is accomplished by heating a mixture containing appropriate amountsof the metal carboxylate, organophosphorous compound and epoxy compoundin the temperature range from about C up to about 200C until solutionhas been effected. Preferably, while effecting solution the temperaturewill not exceed about C. All that is necessary is that the temperaturebe slightly higher than the melting point of the highest meltingcomponent in the mixture. The length of time required to bring aboutsolution will vary depending on the manner and temperature of heating,efficiency of stirring, the particular compounds employed, etc., and isnot critical. As a general rule, however, the heating should not becontinued at elevated temperatures after solution has been effected forsuch prolonged periods so as to promote decomposition of any of thecomponents. While no absolute time for heating can be set out which willencompass all the possible process variations, the point at whichsolution is effected is easily recognized since the mixture will havebeen converted from an opaque, thick, white, paste-like mass to a clearand uniform, homogeneous solution. When this point is reached it may bedesirable, to insure that complete solution has been achieved, tocontinue the heating for an additional short period.

As an alternative to the above procedure, the epoxy compound and eitherone of the other components may be heated separately to obtain asolution and the third component charged later. For example, the epoxycompound and phosphite compound may be mixed and to this solution moltenmetal carboxylate added. In this manner the heat history of thethree-component mix-.

ture can be significantly reduced should this be desirable.

The so-prepared solution may contain from about l to 80% by weight ofthe organophosphorous compound but more preferably the phosphitestabilizer will comprise about 30 to 80 weight percent of the solution.The metal carboxylate will be varied from about I to 35 weight percentof the solution depending on the degree of stabilization required andthe particular end-use application of the resin being stabilized.Sufficient epoxy plasticizer compound must be employed to dissolve thetwo stabilizer components. At least weight percent epoxy compound isusually required, however, the amount generally will not exceed about50% by weight. The amount of epoxy compound required will vary dependingon the solubilities of the particular stabilizer components and theamounts employed.

While not essential, other components may also be present with the epoxycompound, metal carboxylate and organophosphorous compound. These mayserve as supplemental stabilizers, for example where the enduse of thepolyvinyl chloride resin requires such additional stabilization. Formost film applications, the metal carboxylate, organophosphorouscompound and epoxy compound in combination with the polyglycerol partialester, which will be subsequently incorporated, is sufficient to impartthe necessary antifogging and antistatic properties and also adequatelystabilize the polyvinyl chloride resin compositions against thedeleterious effects of oxygen, heat and light. lf desired, however,known supplemental stabilizer compositions may also be added. The totalamount of such supplemental stabilizers will not exceed about by weightof the solution of metal carboxylate, phosphite and epoxy compounds.Supplemental light stabilizers derived from benzophenone and itsderivatives such as 2,2-dihydroxybenzophenone and Z-hydroxybenzophenonemay be added. Other stabilizers such as those derived frombenzotriazoles, triazines, and the phenysalicylates may also beemployed. Phenolic type anti-oxidants may also be used including thehindered phenols containing one or two alkyl groups, preferably tertiaryalkyl groups, immediately adjacent to the hydroxyl group on the aromaticnucleus. Phenolic compounds of the above types include phenol,resorcinol, catechol, cresol, 2,6-di-t-butyl phenol,2,6-di-t-butyl-pcresol, 2,2-bis(4-hydroxyphenyl)propane,methylenebis(2,6-di-6-butyl phenol), methylene-bis(p-cresol), and thelike. Polyvalent metal salts of substituted phenols, such as polyvalentmetal phenolates, are also effective stabilizers and may beadvantageously employed in the present invention.

Once the solution of the metal carboxylate, phosphite and epoxy compoundhas been obtained it may be allowed to stand at ambient conditions forany length of time prior to addition of the polyglycerol partial ester.Thus a masterbatch of these three components can be prepared, stored andemployed as desired by adding thereto the particular polyglycerolpartial esters.

To complete the makeup of the useful stabilizer compositions of thepresent invention a polyglycerol partial ester is added to the solutionof the metal earboxylate, phosphite and epoxy compounds. The amount ofpolyglycerol partial ester will constitute between about 35 and about byweight of the total stabilizer pack age. Depending on whether thestabilization or antifogging and antistatic properties of the resin areof primary importance, the amount of polyglycerol partial ester will bevaried within the stated range. Quite unexpectedly it has been foundthat only when the components comprising the stabilizer system are addedin this manner, i.e., the polyglycerol partial ester added to an alreadyprepared solution of the other three components, are clear, homogeneousliquid stabilizer compositions obtained. Although it is essential thatthe polyglycerol partial ester be added at this stage of the reaction,the manner of additionjs not critical. The partial ester may be added tothe cooled solution or it may be charged to the solution which ismaintained at a temperature up to about l60C. In the latter instance,however, when addition of the polyglycerol partial ester is made to thehot solution the resulting mixture should not be maintained at theseelevated temperatures for prolonged periods since the overalleffectiveness of the resulting stabilizer composition will be reduced.If the final stabilizer solution containing all four components issubjected to an excessive heat history the amount of metal carboxylaterequired for acceptable stabilization is significantly increased and insome instances nearly tripled. lt nevertheless may be advantageous toadd the polyglycerol partial ester to heated solutions to reduce theviscosity, facilitate handling and minimize mixing time. If thistechnique is employed, immediately after a clear solution of the fourcomponents is obtained, the temperature should be reduced. As long thetemperature of the final solution is decreased to about C or lowerwithin about one hour, and more preferably within one-half hour time,after the addition of the polyglycerol partial ester no reduction in theeffectiveness of the stabilizer is observed.

The partial esters employed are obtained by the partial esterificationof polyglycerols with monocarboxylic acids. Only a portion of thehydroxyl functionality of the polyglycerol is utilized. Thepolyglycerols useful for formation of the partial esters areintermolecular glycerol ethers formed by the condensation of two or moreglycerol molecules accompanied by the elimination of water. Suchreactions are known to the art. The number of molecules condensed andmolecular weight distribution of the resulting product is primarily afunction of the temperature employed. In any event, the polyglycerolsare mixtures of products containing from 2 up to as many as 30 glycerolunits condensed. Suitable polyglycerols include, for example,diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol,heptaglycerol, octaglycerol, nonaglycerol, decaglycerol,pentadecaglycerol, triacontaglyeerol and the like. The polyglycerolpartial esters useful for this invention are preferably derived frompolyglycerols containing 2 to It) condensed glycerol units. The desiredphysical characteristics of the stabilizer and ultimate usage of thestabilized resin composition will dictate which polyglycerol orpolyglycerol mixture is to be employed. Other polyether polyols such asthe condensation products of sorbitol, mannitol, pent-aerythritol,trimcthylolpropane or mixtures thereof may also be esterified andemployed in accordance with this invention.

To obtain the partial esters of the polyglycerols one or moremonocarboxylic acids containing from about 6 to about 24 carbon atoms isesterified with the polyglycerol employing known esterificationtechniques, catalysts, etc. The esterification is conducted in such away that the polyglycerol will not be completely esterified, that is,not all the hydroxyl groups will be reacted. For the purpose of thisinvention not more than 75%, and preferably less than about 50%, of thepolyglycerol hydroxyl groups are reacted. The monocarboxylic acids arepreferably fatty acids which are liquids at about room temperature,containing from about 8 to 18 carbon atoms. They may be saturated orcontain unsaturation. Typical acids useful for partial esterification ofthe polyglycerol include octanoic acid, 2-ethylhexanoic acid, capricacid, lauric acid, myristic acid, palmitic acid, isostearic acid, oleicacid, stearic acid, eleostearic acid, palmitoleic acid, linoleic acid,linolenic acid, ricinoleic acid and the like. Mixtures of these andrelated acids may also be employed and are sometimes desirable. Suchmixtures may contain both saturated and unsaturated acids and may beobtained from natural products such as vegetable and animal fats andoils. Coconut oil, cottonseed oil, linseed oil, olive oil, soybean oil,tallow, lard, tall oil, peanut oil and tung oil are typical sourcesuseful to provide mixed acids suitable for esterification with thepolyglycerol. When solely saturated acids are to be esterified with thepolyglycerol a source which provides saturated acids may be employed ora mixture of saturated and unsaturated acids obtained from any sourcemay be hydrogenated prior to use.

In accordance with the present invention the liquid four-componentstabilizer systems are useful with polyvinyl chloride homopolymers andcopolymers. They may be employed with vinyl polymers derived from one ormore vinyl monomers, i.e., containing a group, including: vinylchloride; vinyl bromide; vinyl acetate; vinylidene chloride; lower allylesters; vinyl alkyl ethers; acrylic and methacrylic esters such as ethylacrylate, methyl acrylate and methyl methacrylate; acrylic acid andmethacrylic acid; acrylonitrile and rnethacrylonitrile; and the like.Copolymer compositions obtained by the copolymerization of vinylchloride with vinyl acetate, vinyl chloride with vinyl butyrate, vinylchloride with vinyl propionate, vinyl chloride with vinylidene chloride,vinyl chloride with methylacrylate, vinyl chloride with2-ethylhexylacrylate, and vinyl chloride with two or more monomers suchas mixtures of vinylidene chloride and 2-ethylhexyl acrylate are alsoeffectively stabilized. The present stabilizer compositions may be usedwith acrylonitrilebutadiene-styrene terpolymers, chloroprene polymers,butadiene-styrene polymers, butadiene-acrylonitrilc copolymers,polystyrene, polyacetals and the like. These liquid stabilizers may alsobe employed with blends of one or more of the above polymercompositions. The liquid stabilizer compositions of this invention areespecially effective for use with polyvinyl chloride homopolymer resinssuitable for film applications.

ln general, the amount of liquid stabilizer may range from about 0.5 toabout 25 parts by weight per 100 parts of the vinyl resin. Excellentresults are obtained when about 2.0 to about 6.0 parts by weight of theliquid stabilizer are employed per 100 parts by weight polyvinylchloride. Such compositions exhibit a high degree of resistance tooxidative, thermal and photochemical degradation, in addition to havingexcellent antifogging and antistatic properties.

The present stabilizer compositions, being liquids, are readilyincorporated into the vinyl polymers. Conventional mixing techniques maybe employed. The stabilizers may be used immediately after preparation,or since the present liquid compositions do not separate upon standing,they may be stored and used as required without prior mixing.

Known compounding methods for incorporating ingredients into resins suchas kneading, milling and mixing with a Banbury or ribbon mixer may beemployed. The stabilizer compositions may be added as such, added as amasterbatch solution or emulsified and the emulsion added to thepolymeric material. In general, the resins modified with the stabilizercompositions of this invention possess excellent milling characteristicsand require no special processing. The stabilizer com positions may beused in conjunction with other plasticizing agents such as dioctylphthalate, diisooctyl phthalate, dioctyl adipate, trioctyl phosphate,various polymeric plasticizers and the like. Other compoundingingredients including antioxidants, such as amines and phenols, pigmentsand other colorants, fillers, lubricants, antisticking agents, curingagents and the like may also be utilized therewith. The presentstabilizer compositions and any additional compounding ingredients maybe prepared as a masterbatch and added to the polymer as such or theliquid stabilizer and the additional ingredients may be mixed into theresin separately.

The following examples illustrate the invention more fully, however,they are not intended as a limitation on the scope thereof. In theexamples all parts and percentages are given on a weight basis unlessotherwise indicated.

EXAMPLE I A masterbatch solution of an epoxy compound, metal carboxylateand phosphite stabilizer compound was prepared by thoroughly mixing l2grams zinc stearate, grams tri(nonylphenyl) phosphite and 108 gramsepoxidized soybean oil having an oxirane value of about 6.8 to 7.0. Themixture was heated to about 150C with agitation until a clear yellowishsolution was obtained (about 1 hour). The solution was then allowed tocool and employed as a masterbatch solution for blending with thepolyglycerol partial esters.

The masterbatch solution without the addition of polyglycerol partialester is, by itself, a useful stabilizer for polyvinyl chloride resins.(Diamond example, when parts polyvinyl chloride homopolymer (DiamongShamrock 450), ll) parts epoxidized soybean oil, 20 parts dioctylphthalate, 0.25 part stearic acid and 2.5 parts of the so-preparedmasterbatch solution were blended and milled at 350F for approximately 5minutes, clear, water-white films having excellent heat stability wereobtained.

EXAMPLE n No catalyst was employed for this esterification reac tion,however, similar esterifications were conducted employinghypophosphorous acid.

EXAMPLE Ill Sixty-five grams of the liquid product of Example I and 35grams of the polyglycerol partial ester of Example ll were mixed at roomtemperature and a clear, homogeneous liquid obtained. Samples of thesomepared solution showed no evidence of phase separation after storagefor over 10 months at room temperature. The stabilizer solution wasincorporated into polyvinyl chloride homopolymer in accordance with thefollowing recipe:

Polyvinyl chloride (Diamond Shamrock 40) 40 parts Epoxidized soybean oil(6.8-7.0 oxirane value) 9 parts Dioctyl azelate 9 parts Stearic acid 0.5part Liquid stabilizer 3.0 parts The ingredients were blended and milledat 350F for about 5 minutes. The water-white films were suitable for useas hard packaging films and had excellent lubricity or slip". The films,in addition to having excellent heat stability, also had markedlyimproved antifogging and antistatic properties.

When 35 grams of the partial ester of Example ll, 4 grams zinc stearate,25 grams tri(nonylphenyl) phosphite and 36 grams epoxidized soybean oilwere combined as a unit charge and blended together at room temperaturea paste-like mass was recovered. When this mixture was heated up to ashigh as 160C a relatively clear melt was obtained but upon cooling toroom temperature and upon standing there was appreciable phaseseparation and a precipitate settled from solution. This precipitatecould not be redissolved with any amount of treatment to obtain a clearsolution. No amount of heating or any other treatment was capable ofproducing clear. homogeneous liquids which retained their homogeneityupon standing when all the four components were combined as a unitcharge.

EXAMPLE IV A liquid stabilizer composition having superior antifoggingand antistatic properties was prepared as follows: 280 grams zincstearate, 200 grams epoxidized soybean oil and 520 gramstri(nonylphenyl) phosphite were heated at 150C and the heatingterminated when a clear solution was obtained. After cooling the mixtureto about 60C, 3000 grams of the polyglycerol partial ester of Example llwas added with stirring. The resulting clear, homogeneous liquidstabilizer was compounded with polyvinyl chloride resin to prepare ameat packaging film in accordance with the following recipe:

Polyvinyl chloride homopolymer 100 parts (Diamond Shamrock 450i Dioctyladipate l8 parts Epoxidized soybean oil 9 parts Ethylene-bis-stearamide0. 5 part Liquid stabilizer 2.5 parts The ingredients were blended andmilled at 350F for about 5 minutes. Thirty-five mil and 3 mil clearsheets were obtained.

Oven heat stability tests were conducted using l inch X l inch squarescut from the 35 mil sheet by placing the samples on eight glass traysfitted on a rotating device in an electric oven maintained at 375F. Theheating is continued for minutes with one glass slide being removedafter each ten-minute interval. Each slide is cooled after removal fromthe oven and the test specimen removed for observation and comparison.Samples stabilized in accordance with the present invention withstoodthe entire eighty-minute heating period without failure, that is,without degradation or severe discoloration and charring. After 80minutes the samples were clear and had an amber color.

A 3 mil sheet was employed to evaluate the antifogging properties bystretching the film over a 250 ml beaker 2/3 full of water heated to80C. This is is conventional test employed in the art to measureresistance of films to fogging. The film compounded in accordance withthe above recipe showed no fogging (condensation of water droplets onthe film) even after 10 minutes.

EXAMPLE V EXAMPLE Vt Sixty-five grams of the liquid prepared in Example1 was combined with 35 grams of the partial ester of a polyglycerolprepared by the esterification of l mol diglycerol with l.3 mols oleicacid employing hypophosphorous acid catalyst. Polyvinyl chloridehomopolymer resins containing about 3 parts of the resulting liquidstabilizer and tested in accordance with the above-described procedureshad superior antifogging properties and heat stability.

EXAMPLE Vll l .5 Parts zinc stearate, 5 parts epoxidized soybean oil andI0 parts tri(nonylphenyl) phosphite were heated to about l40C to effectsolution. Eighty-three parts of an ester prepared by the reaction of 1mol triglycerol with 2 mols mixed fatty acids was then added to thecooled solution. The resulting stabilizer solution was employed in thefollowing recipe:

Polyvinyl chloride copolymer ()0 mol Z vinyl chloride 10 mol vinylacetatel l00 parts Impact modifier (Rohm 81. Hurts KM636] l 0 parts-continued Epoxidized soybean oil parts Liquid stabilizer 2.5 partsEXAMPLE VIlI Diphenyl decyl phosphite (l3 grams) was heated (150C max.)with 7 grams zinc stcarate and 5 grams epoxidized soybean oil until aclear solution was obtained. The solution was cooled and 75 grams of theester of Example I] added thereto. The resulting stabilizer solution.while more viscous than solutions prepared with tri(nonylphenyl)phosphite, flowed readily at room temperature. Polyvinyl chloride resinhomopolymer stabilized with this stabilizer solution had good physicalproperties, heat stability and anti-fogging properties.

EXAMPLE IX To demonstrate the versatility of the present process for thepreparation of improved liquid stabilizers with antifogging andantistatic properties, Example IV was repeated heating to a maximumtemperature of 135C to effect solution of the zinc stearate, epoxidizedsoybean oil and tri(nonylphenyl) phosphite. The polyglycerol partialester was then added to the hot (I35C) solution and the mixture cooledto about 50C within about 30 to 45 minutes. The liquid stabilizerprepared in this manner was comparable in all respects to the stabilizercomposition of Example IV.

The procedure was repeated except that the solution was not immediatelycooled after addition of the polyglycerol partial ester. The stabilizersolutions obtained were unacceptable. For example, when the mixture wasmaintained at 135C for 24 hours the brilliance of color imparted by thestabilizer is lost and water-white films are no longer obtained. Insteadthe films have a yellowish discoloration. These films, when subjected toovenaging at 375F develop more discoloration after 10-20 minutes thanresin samples stabilized with the liquid compositions prepared inaccordance with this invention after about 80 minutes oven-aging.

We claim:

I. A method for stabilizing vinyl polymer resin to impart antifoggingand antistatic properties and improve hcat stability which comprises:

l. admixing at a temperature of l()()C to 200C until solution has beeneffected (a) 5 to 50 parts by weight aliphatic or cycloaliphatic epoxycompound containing from It) to I carbon atoms. (b) l to 35 partspolyvalent metal salt of a monocarboxylic acid containing from 6 to 26carbon atoms and (c) l() to 80 parts organophosphorous compound of theformula wherein R is a hydrocarbon radical containing from I to 24carbon atoms and selected from the group consisting of aryl, alkyl,alkaryl, aralkyl. and cycloaliphatic and R and R" and hydrogen or R;

2. adding 35 to parts ofa partial ester ofa polyglycerol having not morethan 75% of the polyglycerol hydroxyl groups reacted and derived from aC monocarboxylic acid and a polyglycerol containing 2 to 30 condensedglycerol units; and

3. incorporating 0.5 to 25 parts by weight of the resulting liquidstabilizer into I00 parts polyvinyl chloride homopolymer or copolymer.

2. The method of claim 1 where in step l the temperature does not exceedI65C, (a) contains from 20 to I50 carbon atoms. (b) is the zinc salf ora mixture of calcium and zinc salts of an aliphatic monocarboxylic acidcontaining from 12 to 20 carbon atoms, (c) is a phosphite compound withR groups containing 6 to 20 carbon atoms and the polyglycerol partialester has less than 50% of the polyglycerol hydroxyl groups reacted andis derived from a fatty acid containing 8 to 18 carbon atoms and apolyglycerol containing 2 to 20 condensed glycerol units.

3. The method of claim 2 wherein Z to 6 parts by weight of the liquidstabilizer is incorporated into a film-forming polyvinyl chloridepolymer.

4. The method of claim 3 wherein (a) is an epoxidized naturally occuringoil, (b) is zinc stearate and (c) is tri(nonylphenyl) phosphite.

5. The stabilized resin composition of claim I.

1. A METHOD FOR STABILIZING VINYL POLYMER RESIN TO IMPART ANTIFOGGINGAND ANTISTATIC PROPERTIES AND IMPROVE HEAT STABILITY WHICH COMPRISES: 1.ADMIXING AT A TEMPERTURE OF 100*C TO 200*C UNTIL SOLUTION HAS BEENEFFECTED (A) 5 TO 50 PARTS BY WEIGHT ALIPHATIC OR CYCLOALIPHATIC EPOXYCOMPOUND CONTAINING FROM 10 TO 180 CARBON ATOMS, (B) 1 TO 35 PARTSPOLYVALENT METAL SALT OF A MONOCARBOYLIC ACID CONTAINING FROM 6 TO 26CARBON ATOMS AND (C) 10 TO 80 PARTS ORGANOPHOSPHOROUS COMPOUND OF THEFORMULA
 2. ADDING 35 TO 85 PARTS OF A PARTIAL ESTER OF A POLYGLYCEROLHAVING NOT MORE THAN 75% OF THE POLYGLYCEROL HYDROXYL GROUPS REACTED ANDDERIVED FROM A C6-24 MONOCARBOXYLI ACID AND A POLYGLYCEROL CONTAINING 2TO 30 CONDENSED GLYCEROL UNITS; AND
 2. The method of claim 1 where instep (1) the temperature does not exceed 165*C, (a) contains from 20 to150 carbon atoms, (b) is the zinc salf or a mixture of calcium and zincsalts of an aliphatic monocarboxylic acid containing from 12 to 20carbon atoms, (c) is a phosphite compound with R groups containing 6 to20 carbon atoms and the polyglycerol partial ester has less than 50% ofthe polyglycerol hydroxyl groups reacted and is derived from a fattyacid containing 8 to 18 carbon atoms and a polyglycerol containing 2 to20 condensed glycerol units.
 2. adding 35 to 85 parts of a partial esterof a polyglycerol having not more than 75% of the polyglycerol hydroxylgroups reacted and derived from a C6-24 monocarboxylic acid and apolyglycerol containing 2 to 30 condensed glycerol units; and 3.incorporating 0.5 to 25 parts by weight of the resulting liquidstabilizer into 100 parts polyvinyl chloride homopolymer or copolymer.3. The method of claim 2 wherein 2 to 6 parts by weight of the liquidstabilizer is incorporated into a film-forming polyvinyl chloridepolymer.
 3. INCORPORATING 0.5 TO 25 PARTS BY WEIGHT OF THE RESULTINGLIQUID STABILIZER INTO 100 PARTS POLYVINYL CHLORIDE HOMOPOLYMER ORCOPOLYMER.
 4. The method of claim 3 wherein (a) is an epoxidizednaturally occuring oil, (b) is zinc stearate and (c) is tri(nonylphenyl)phosphite.
 5. The stabilized resin composition of claim 1.